Well, there must be some way to shake him out of his apathy.
We have a 14 yr old S at home, and I will still put on a cute nightie, but put on a robe over it, and every now and then let H have a peek. so, you will go for several weeks without sex before you will get tired of waiting for him to initiate? How often will you do it if you initiate more often? When he starts to have sex, without waiting for foreplay, why not say hey let's take it slow, this time. About the flirting, just go ahead and flirt with him, anyway. Who knows? And it can't hurt. And when he is working around the house, go do the things to him you want him to do to you, like the nuzzling. Or flash him while he's cutting the grass, if the neighbors can't see, I did that the other day.
Get the book the five love languages and see what his love language is, and let him read it to see what your is.